In recent years, substantial amount of research work has been done in order to improve the sensitivity and resolution of the electro spray mass spectrometry (ESI-MS). The key technology is how to enhance the transmission efficiency of sampling ion generated by ESI and transferred into the mass spectrum more effectively. The air amplifier is an aerodynamics device, which focuses ions into the inlet of MS using Coanda effect and Venturi effect.
The working process of the air amplifier can be described as follows. The gas enters into the chamber from the inlet, and the gas was extruded in the gap and its velocity is increased. The gas moves along the wall by the Coanda effect and a pressure drop generated by the high speed gas velocity occurs due to the Venturi effect, which induces the airflow around the wall surface. The ion plume is focused and speeded up in the center area of the ion focusing groove. Therefore, the transmission efficiency is improved in this way.
People have studied the role of commercial air amplifier in electrospray mass spectrometry system, which can improve the quantity of ions. However, there are disadvantages of the commercial air amplifier such as the large size, complication structure and high cost. These disadvantages are not favorite for the miniaturization of the ESI-MS system and not suitable for the nano-ESI source.